1. Field of the Invention
This invention relates to a chemical process monitor and a monitoring process wherein a chemical process control means and an adjustment means for adjusting the controlled process parameter are simultaneously monitored. More particularly, this invention relates to a water treatment monitor system and a monitoring process wherein a water treatment controller and a positive displacement pump output monitor are simultaneously monitored. Still further, the present invention relates to a chemical process monitor system and a monitoring process wherein a multiplicity of chemical process control means and a multiplicity of adjustment means for adjusting the controlled process parameters are simultaneously monitored.
2. Brief Description of the Prior Art
Several methods are known for controlling the feeding of chemicals and solutions from holding tanks and the like into reactors, process streams or treatment streams. The simplest way is to employ a chemical feed pump with an on/off switch and transfer lines to move the chemical or solution from the holding tank to the reactor or the like. This method requires the costly presence of a human operator for this job and may be unsuitable in many situations (e.g. where the exact time for feeding is unpredictable or where the pump location is in an out-of-the-way location).
Other methods employ electromechanical control means (e.g. standard controllers) to determine when the chemicals or solutions should be transferred. The control means may either measure a property in the reactor or end-use stream or automatically time when the chemical should be fed. When either of these effects are sensed by the control means, it generates a signal to turn on the pump. The controller may also generate a second signal to turn off the pump when the measured property has changed to the desired level or when the feeding time has been completed. The use of such control means may reduce the cost of constant human monitoring; but it does not monitor the actual operation of the feed pump. Pumps may fail for a variety of reasons, including loss of prime, fouled check valves and blown fuses. Additional surveillance systems may be employed to monitor the operation of the pump and provide an alarm signal when the pump goes on or remains off. However, this may lead to the creation of many alarm signals, especially in those situations where it is normal for the pump to be on and off many times a day. In such cases, the operator' s attention to true pump failures will be lessened. Undetected pump failures may cause process shutdowns or the production of poor quality products or untreated process streams or a combination of these undesirable effects within a short amount of time.
The present invention provides a means for simultaneously monitoring chemical process control means such as pump controllers and adjustment means for adjusting the controlled process parameters (e.g. pumps) and providing an alarm whenever the adjustment means fails to respond to the control means for whatever reason, yet allows enough time for the adjustment means to correct itself (e.g. to reprime itself as in the case of a pump) and avoid a false or unnecessary alarm signal from being made.